The present invention relates to containerized freight transportation systems and methods and, more particularly, containerized freight transportation systems incorporating a marine vessel such as a barge.
Transportation of containerized freight has proven to be efficient and cost-effective when utilized in a marine environment. It is now quite common for barges and freighters, the latter more specifically named container ships, to transport containerized cargo. Typically, the cargo is first stowed within enclosed, sealable metal containers which are made in standardized lengths, such as 40 feet, and having standardized width and height dimensions. Once filled with cargo at a customer's location, the containers are sealed and transported by tractor trailer or rail to a marine terminal, where they are loaded upon a barge or container ship by container cranes.
Container cranes are relatively expensive, typically costing several million dollars each. Such cranes typically comprise an elevated bridge or superstructure mounted on rails set in the marine terminal. The bridge supports a boom which is sufficiently elevated to allow the marine vessel to be loaded or unloaded to sail and moor beneath it. The container crane includes a carriage movably mounted on the boom having a winch which lifts containers singly from the dock between the support legs of the superstructure, transports them to a desired position above the load deck of the vessel, then lowers the containers to a preselected location. Marine vessels loaded in this fashion typically transport containers stacked several containers high, or in greater stacks. Once the containers have been stacked on the load deck, they may be lashed into position by a series of cables which are attached to the deck. Containers stored below the weather deck of the marine vessel typically are secured in racks which are dimensioned to receive containers of a particular size.
A disadvantage with such a crane system for loading and unloading containers from a marine vessel is that such systems are quite expensive, require extensive site preparation, significant space for erection and significant wharf strength, and can handle only a single container at a time (although some marine terminals have more than one container crane on a set of tracks). Accordingly, there is a need for a system and method of loading, transporting, and unloading containerized cargo from marine vessels which can be implemented and operated at a relatively low cost and does not require significant site preparation or space.